This invention generally relates to portable medical diagnostic equipment. In particular, the invention relates to equipment used to monitor patients at a remote location or during transport in a hospital or other patient care setting.
When providing medical care to patients, it is frequently necessary to monitor the patient using medical monitoring instruments. One type of instrument, the patient monitor, is capable of monitoring the patient to acquire electrocardiogram data, cardiac output data, respiration data, pulse oximetry data, blood pressure data, temperature data and other parameter data. In particular, lightweight portable monitors exist which can be moved with the patient, allowing continuous monitoring during patient transport. Also these portable monitors can be used at locations remote from a central station in a hospital facility or other patient care setting.
To facilitate monitoring at remote locations or during patient transport, modern portable patient monitors are powered by rechargeable batteries. Extended-use batteries, with quick recharge times, help maximize monitor availability. Advanced monitors have a smart battery management system which maximizes battery life, reducing maintenance and replacement. These patient monitors can also be plugged into any conventional electrical power system for use, e.g., at the patient""s bedside, before and/or after the patient is transported. At the bedside, advanced patient monitors can be hardwired to a central station via a local area network (LAN) for enhanced patient surveillance efficiency. In addition, the most advanced patient monitors have a built-in wireless option which enables the monitor to go mobile without sacrificing connectivity. Such monitors also support importation of demographic and laboratory data from a hospital information system for increased efficiency.
Portable patient monitors with integral battery power supply are commercially available in a compact, ergonomic package which allows easy handling. Typically such monitors have a drop-tested rugged design which allows them to withstand the punishment of the demanding intra-hospital transport applications. Mounting options make these monitors ideally suited for headboard/footboard, siderail, rollstand and IV pole use. The compact design is achieved in part through the use of flat display panels. The color or monochrome screen accommodates all numerics and multiple waveforms.
In addition to displaying waveforms and numerics representing the data being acquired, advanced patient monitors have a central processing system which stores and analyzes the acquired data. In particular, the central processing system is programmed with algorithms for analyzing the acquired data. The central processing system controls the transfer of data to the display panel for display and to the LAN via either a hardwired or wireless connection.
Known patient monitors incorporate an optional radiofrequency local area network (RF LAN) feature that utilizes antenna diversity technology. Antenna diversity technology uses the stronger signal from two antennae to reduce multipath RF interference and provide redundancy. To maximize transmissions, the antennae should be mounted a minimum distance of one-quarter wavelength apart on the top surface of the monitor. An antenna mounted on a portable device is exposed to the risk of damage during monitor movement. Damage to the antenna could result in a non-functional RF LAN subsystem in the monitor. Thus, there is a need for a portable wireless instrument in which the antennae are not inherently susceptible to damage.
The present invention mitigates potential damage to an antenna of a portable wireless instrument, such as a patient monitor, by incorporating the antenna inside the instrument handle. The handle is made of material which does not negatively impact RF transmissions and which is sufficiently rugged to protect the antennae against damage when the instrument is subjected to impacts. The preferred material is a plastic such as polycarbonate.
In accordance with the preferred embodiment of the invention, a pair of antennae are integrated into the handle of a portable patient monitor to enable wireless communication with a central station. The handle comprises front and rear molded pieces which are fastened together, the antennae being mounted to one of the molded pieces. Each antenna is securely supported in a respective pair of slots formed in respective ribs of the molded piece. In the assembled state, the front and rear molded pieces of the handle protect the antennae against impacts.
The invention is not limited in application to handles designed to house two or more antennae. The construction technique disclosed herein can be employed in portable instruments having a single antenna.